Chemical mechanical polishing pad

ABSTRACT

A chemical mechanical polishing pad is provided containing a polishing layer having a polishing surface, wherein the polishing layer comprises a reaction product of ingredients, including: an isocyanate terminated urethane prepolymer; and, a curative system, containing a high molecular weight polyol curative; and, a difunctional curative.

This application is a continuation of U.S. application Ser. No.14/261,893, filed Apr. 25, 2014.

The present invention relates to chemical mechanical polishing pads andmethods of making and using the same. More particularly, the presentinvention relates to a chemical mechanical polishing pad comprising apolishing layer, wherein the polishing layer exhibits a density ofgreater than 0.6 g/cm³; a Shore D hardness of 40 to 60; an elongation tobreak of 125 to 300%; a G′ 30/90 ratio of 1.5 to 4; a tensile modulus of100 to 300 (MPa); a wet cut rate of 4 to 10 μm/min; a 300 mm TEOSremoval rate to Shore D hardness ratio (TEOS_(300-RR)/Shore D hardness)of ≥28; and, wherein the polishing layer has a polishing surface adaptedfor polishing the substrate.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting and dielectric materialsare deposited onto and removed from a surface of a semiconductor wafer.Thin layers of conducting, semiconducting and dielectric materials maybe deposited using a number of deposition techniques. Common depositiontechniques in modern wafer processing include physical vapor deposition(PVD), also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD) and electrochemicalplating, among others. Common removal techniques include wet and dryisotropic and anisotropic etching, among others.

As layers of materials are sequentially deposited and removed, theuppermost surface of the wafer becomes non-planar. Because subsequentsemiconductor processing (e.g., metallization) requires the wafer tohave a flat surface, the wafer needs to be planarized. Planarization isuseful for removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches and contaminated layers or materials.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize or polish work piecessuch as semiconductor wafers. In conventional CMP, a wafer carrier, orpolishing head, is mounted on a carrier assembly. The polishing headholds the wafer and positions the wafer in contact with a polishinglayer of a polishing pad that is mounted on a table or platen within aCMP apparatus. The carrier assembly provides a controllable pressurebetween the wafer and polishing pad. Simultaneously, a polishing medium(e.g., slurry) is dispensed onto the polishing pad and is drawn into thegap between the wafer and polishing layer. To effect polishing, thepolishing pad and wafer typically rotate relative to one another. As thepolishing pad rotates beneath the wafer, the wafer sweeps out atypically annular polishing track, or polishing region, wherein thewafer's surface directly confronts the polishing layer. The wafersurface is polished and made planar by chemical and mechanical action ofthe polishing layer and polishing medium on the surface.

Pad surface “conditioning” or “dressing” is critical to maintain aconsistent polishing surface for stable polishing performance. Over timethe polishing surface of the polishing pad wears down, smoothing overthe microtexture of the polishing surface—a phenomenon called “glazing”.Polishing pad conditioning is typically achieved by abrading thepolishing surface mechanically with a conditioning disk. Theconditioning disk has a rough conditioning surface typically comprisedof embedded diamond points. The conditioning disk is brought intocontact with the polishing surface either during intermittent breaks inthe CMP process when polishing is paused (“ex situ”), or while the CMPprocess is underway (“in situ”). Typically the conditioning disk isrotated in a position that is fixed with respect to the axis of rotationof the polishing pad, and sweeps out an annular conditioning region asthe polishing pad is rotated. The conditioning process as described cutsmicroscopic furrows into the pad surface, both abrading and plowing thepad material and renewing the polishing texture.

Semiconductor devices are becoming increasingly complex with finerfeatures and more metallization layers. This trend requires improvedperformance from polishing consumables in order to maintain planarityand limit polishing defects. The latter can create electrical breaks orshorts of the conducting lines that would render the semiconductordevice non-functional. It is generally known that one approach to reducepolishing defects, such as micro-scratches or chatter marks, is to use asofter polishing pad.

A family of soft polyurethane polishing layers are disclosed by James,et al. in U.S. Pat. No. 7,074,115. James et al. discloses a polishingpad comprising a the reaction product of an isocyanate-terminatedurethane prepolymer with an aromatic diamine or polyamine curative,wherein the reaction product exhibits a porosity of at least 0.1 volumepercent, a KEL energy loss factor at 40° C. and a 1 rad/sec of 385 to7501/Pa, and a modulus E′ at 40° C. and 1 rad/sec of 100 to 400 MPa.

As described above, it is necessary to diamond condition the surface ofchemical mechanical polishing pads to create a favorable microtexturefor optimum polishing performance. However, it is difficult to createsuch texture in conventional polishing layer materials, such as thosedescribed by James et al., because these materials exhibit a highductility, as measured by tensile elongation to break values. As aresult, when these materials are subjected to conditioning with adiamond conditioning disk, rather than cutting furrows into the pad'ssurface, the diamonds in the conditioning disk simply push the padmaterial aside without cutting. Hence, very little texture is created inthe surface of these conventional materials as a result of conditioningwith a diamond conditioning disk.

Another related problem with these conventional chemical mechanicalpolishing pad materials arises during the machining process to formmacro groove patterns in the pad surface. Conventional chemicalmechanical polishing pads are typically provided with a groove patterncut into their polishing surface to promote slurry flow and to removepolishing debris from the pad-wafer interface. Such grooves arefrequently cut into the polishing surface of the polishing pad eitherusing a lathe or by a CNC milling machine. With soft pad materials,however, a similar problem to that of diamond conditioning occurs, suchthat after the cutting bit has passed, the pad material simply reboundsand the grooves formed close in on themselves. Thus groove quality ispoor and it is more difficult to successfully manufacture commerciallyacceptable pads with such soft materials. This problem worsens as thehardness of the pad material decreases.

Accordingly, there is a continuing need for chemical mechanicalpolishing pads that provide a physical property profile that correlateswell with that associated with low defect formulations, but which alsoimparts enhanced conditionability to the polishing layer (i.e., exhibitsa cut rate of 25 to 150 μm/hr).

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; and wherein the high molecular weight polyol curativehas an average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt% of a difunctional curative.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; wherein the high molecular weight polyol curative hasan average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt %of a difunctional curative; and, wherein the polishing surface isadapted for polishing a substrate selected from the group consisting ofat least one of a magnetic substrate, an optical substrate and asemiconductor substrate.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; and wherein the high molecular weight polyol curativehas an average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt% of a difunctional curative; wherein the curative system has aplurality of reactive hydrogen groups and the isocyanate terminatedurethane prepolymer has a plurality of unreacted NCO groups; and,wherein a stoichiometric ratio of the reactive hydrogen groups to theunreacted NCO groups is 0.85 to 1.15.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; wherein the high molecular weight polyol curative hasan average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt %of a difunctional curative; and, wherein the polishing layer exhibits adensity of greater than 0.6 g/cm³; a Shore D hardness of 40 to 60; anelongation to break of 125 to 300%; a G′ 30/90 ratio of 1.5 to 4; atensile modulus of 100 to 300 (MPa); a wet cut rate of 4 to 10 μm/min;and, a 300 mm TEOS removal rate to Shore D hardness ratio(TEOS_(300-RR)/Shore D hardness) of ≥28.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.95 to 9.25 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; wherein the high molecular weight polyol curative hasan average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt %of a difunctional curative; and, wherein the polishing layer exhibits adensity of greater than 0.6 g/cm³; a Shore D hardness of 40 to 60; anelongation to break of 125 to 300%; a G′ 30/90 ratio of 1.5 to 4; atensile modulus of 100 to 300 (MPa); a wet cut rate of 4 to 10 μm/min;and, a 300 mm TEOS removal rate to Shore D hardness ratio(TEOS_(300-RR)/Shore D hardness) of ≥28.

The present invention provides a chemical mechanical polishing pad,comprising: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, a curative system, comprising: 10 to 60 wt %of a high molecular weight polyol curative, wherein the high molecularweight polyol curative has a number average molecular weight, M_(N), of2,500 to 100,000; wherein the high molecular weight polyol curative hasan average of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt %of a difunctional curative; and, wherein the polishing surface has aspiral groove pattern formed therein; wherein the polishing surface isadapted for polishing a substrate selected from the group consisting ofat least one of a magnetic substrate, an optical substrate and asemiconductor substrate.

present invention provides a method of making a chemical mechanicalpolishing pad according to the present invention, comprising: providingan isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; and, providing a curative system, comprising: 10to 60 wt % of a high molecular weight polyol curative, wherein the highmolecular weight polyol curative has a number average molecular weight,M_(N), of 2,500 to 100,000; and wherein the high molecular weight polyolcurative has an average of 3 to 10 hydroxyl groups per molecule; and, 40to 90 wt % of a difunctional curative; and, combining the isocyanateterminated urethane prepolymer and the curative system to form acombination; allowing the combination to react to form a product;forming a polishing layer from the product; and, forming the chemicalmechanical polishing pad with the polishing layer.

present invention provides a method of making a chemical mechanicalpolishing pad according to the present invention, comprising: providingan isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %unreacted NCO groups; providing a plurality of microelements; and,providing a curative system, comprising: 10 to 60 wt % of a highmolecular weight polyol curative, wherein the high molecular weightpolyol curative has a number average molecular weight, M_(N), of 2,500to 100,000; and wherein the high molecular weight polyol curative has anaverage of 3 to 10 hydroxyl groups per molecule; and, 40 to 90 wt % of adifunctional curative; and, combining the isocyanate terminated urethaneprepolymer, the plurality of microelements and the curative system toform a combination; allowing the combination to react to form a product;forming a polishing layer from the product; and, forming the chemicalmechanical polishing pad with the polishing layer.

The present invention provides a method of polishing a substrate,comprising: providing a chemical mechanical polishing apparatus having aplaten; providing at least one substrate; providing a chemicalmechanical polishing pad according to the present invention; installingonto the platen the chemical mechanical polishing pad; optionally,providing a polishing medium at an interface between the polishingsurface and the substrate; creating dynamic contact between thepolishing surface and the substrate, wherein at least some material isremoved from the substrate.

The present invention provides a method of polishing a substrate,comprising: providing a chemical mechanical polishing apparatus having aplaten; providing at least one substrate, wherein the at least onesubstrate is selected from the group consisting of at least one of amagnetic substrate, an optical substrate and a semiconductor substrate;providing a chemical mechanical polishing pad according to the presentinvention; installing onto the platen the chemical mechanical polishingpad; optionally, providing a polishing medium at an interface betweenthe polishing surface and the substrate; creating dynamic contactbetween the polishing surface and the substrate, wherein at least somematerial is removed from the substrate.

DETAILED DESCRIPTION

The chemical mechanical polishing pad of the present invention has apolishing layer that exhibits both a desirable balance of physicalproperties that correlates well with low defect polishing performanceand conditionability to facilitate the formation of microtexture using adiamond conditioning disk, while maintaining a high polishing rate.Accordingly, the balance of properties enabled by the polishing layer ofthe present invention provides the ability to, for example, polishsemiconductor wafers at an efficient rate without damaging the wafersurface by creating micro-scratch defects that could compromise theelectrical integrity of the semiconductor device.

The term “polishing medium” as used herein and in the appended claimsencompasses particle containing polishing solutions and non particlecontaining polishing solutions, such as abrasive free and reactiveliquid polishing solutions.

The term “TEOS_(300-RR)/Shore D Hardness” as used herein and in theappended claims is the ratio of TEOS removal rate to Shore D hardnessfor a given polishing layer defined as follows:TEOS_(300-RR)/Shore D Hardness=(TEOS_(300-RR))÷Shore D Hardnesswherein the TEOS_(300-RR) is the TEOS removal rate in A/min for thepolishing layer measured according to the procedure set forth hereinbelow in the Polishing Examples; and, the Shore D Hardness is thehardness of the polishing layer measured according to ASTM D2240.

The term “G′ 30/90 ratio” as used herein and in the appended claims isthe ratio of the shear modulus (at 30° C.), G′₃₀, to the shear modulus(at 90° C.), G′₉₀, for a given polishing layer defined as follows:G′30/90 ratio=G′ ₃₀ ÷G′ ₉₀wherein G′₃₀ and G′₉₀ for the polishing layer are measured according toASTM D5279-13 at 30° C. and 90° C., respectively.

The chemical mechanical polishing pad of the present invention,comprises: a polishing layer having a polishing surface, wherein thepolishing layer comprises a reaction product of ingredients, comprising:an isocyanate terminated urethane prepolymer having 8.5 to 9.5 wt %(preferably, 8.75 to 9.5 wt %; more preferably, 8.75 to 9.25; mostpreferably, 8.95 to 9.25 wt %) unreacted NCO groups; and, a curativesystem, comprising: 10 to 60 wt % (preferably, 15 to 50 wt %; morepreferably, 20 to 40 wt %; most preferably, 20 to 30 wt %) of a highmolecular weight polyol curative having a number average molecularweight, M_(N), of 2,500 to 100,000 (preferably 5,000 to 50,000; morepreferably 7,500 to 25,000; most preferably, 10,000 to 12,000) and anaverage of three to ten (preferably, four to eight; more preferably,five to seven; most preferably, six) hydroxyl groups per molecule; and,40 to 90 wt % (preferably, 50 to 85 wt %; more preferably, 60 to 80 wt%; most preferably, 70 to 80 wt %) of a difunctional curative.

The polishing surface of the polishing layer of the chemical mechanicalpolishing pad of the present invention is adapted for polishing asubstrate. Preferably, the polishing surface is adapted for polishing asubstrate selected from at least one of a magnetic substrate, an opticalsubstrate and a semiconductor substrate. More preferably, the polishingsurface is adapted for polishing a semiconductor substrate. Mostpreferably, the polishing surface is adapted for polishing a TEOS oxidesurface of a semiconductor substrate.

Preferably, the polishing surface has macrotexture selected from atleast one of perforations and grooves. Perforations can extend from thepolishing surface part way or all the way through the thickness of thepolishing layer. Preferably, grooves are arranged on the polishingsurface such that upon rotation of the chemical mechanical polishing padduring polishing, at least one groove sweeps over the surface of thesubstrate being polished. Preferably, the polishing surface hasmacrotexture including at least one groove selected from the groupconsisting of curved grooves, linear grooves and combinations thereof.

Preferably, polishing layer of the chemical mechanical polishing pad ofthe present invention has a polishing surface with a macrotexturecomprising a groove pattern formed therein. Preferably, the groovepattern comprises a plurality of grooves. More preferably, the groovepattern is selected from a groove design. Preferably, the groove designis selected from the group consisting of concentric grooves (which maybe circular or spiral), curved grooves, cross hatch grooves (e.g.,arranged as an X-Y grid across the pad surface), other regular designs(e.g., hexagons, triangles), tire tread type patterns, irregular designs(e.g., fractal patterns), and combinations thereof. More preferably, thegroove design is selected from the group consisting of random grooves,concentric grooves, spiral grooves, cross-hatched grooves, X-Y gridgrooves, hexagonal grooves, triangular grooves, fractal grooves andcombinations thereof. Most preferably, the polishing surface has aspiral groove pattern formed therein. The groove profile is preferablyselected from rectangular with straight side walls or the groove crosssection may be “V” shaped, “U” shaped, saw tooth, and combinationsthereof.

The isocyanate terminated urethane prepolymer used in the formation ofthe polishing layer of the chemical mechanical polishing pad of thepresent invention preferably comprises: a reaction product ofingredients, comprising: a polyfunctional isocyanate and a prepolymerpolyol.

Preferably, the polyfunctional isocyanate is selected from the groupconsisting of an aliphatic polyfunctional isocyanate, an aromaticpolyfunctional isocyanate and a mixture thereof. More preferably, thepolyfunctional isocyanate is a diisocyanate selected from the groupconsisting of 2,4-toluene diisocyanate; 2,6-toluene diisocyanate;4,4′-diphenylmethane diisocyanate; naphthalene-1,5-diisocyanate;tolidine diisocyanate; para-phenylene diisocyanate; xylylenediisocyanate; isophorone diisocyanate; hexamethylene diisocyanate;4,4′-dicyclohexylmethane diisocyanate; cyclohexanediisocyanate; and,mixtures thereof.

Preferably, the prepolymer polyol is selected from the group consistingof diols, polyols, polyol diols, copolymers thereof, and mixturesthereof. More preferably, the prepolymer polyol is selected from thegroup consisting of polyether polyols (e.g.,poly(oxytetramethylene)glycol, poly(oxypropylene)glycol,poly(oxyethylene)glycol); polycarbonate polyols; polyester polyols;polycaprolactone polyols; mixtures thereof; and, mixtures thereof withone or more low molecular weight polyols selected from the groupconsisting of ethylene glycol; 1,2-propylene glycol; 1,3-propyleneglycol; 1,2-butanediol; 1,3-butanediol; 2-methyl-1,3-propanediol;1,4-butanediol; neopentyl glycol; 1,5-pentanediol;3-methyl-1,5-pentanediol; 1,6-hexanediol; diethylene glycol; dipropyleneglycol; and, tripropylene glycol. Still more preferably, the prepolymerpolyol is selected from the group consisting of at least one ofpolytetramethylene ether glycol (PTMEG); polypropylene ether glycols(PPG), and polyethylene ether glycols (PEG); optionally, mixed with atleast one low molecular weight polyol selected from the group consistingof ethylene glycol; 1,2-propylene glycol; 1,3-propylene glycol;1,2-butanediol; 1,3-butanediol; 2-methyl-1,3-propanediol;1,4-butanediol; neopentyl glycol; 1,5-pentanediol;3-methyl-1,5-pentanediol; 1,6-hexanediol; diethylene glycol; dipropyleneglycol; and, tripropylene glycol. Most preferably, the prepolymer polyolis primarily (i.e., ≥90 wt %) PTMEG.

Preferably, the isocyanate terminated urethane prepolymer has anunreacted isocyanate (NCO) concentration of 8.5 to 9.5 wt % (morepreferably, 8.75 to 9.5 wt %; still more preferably, 8.75 to 9.25; mostpreferably, 8.95 to 9.25 wt %). Examples of commercially availableisocyanate terminated urethane prepolymers include Imuthane® prepolymers(available from COIM USA, Inc., such as, PET-80A, PET-85A, PET-90A,PET-93A, PET-95A, PET-60D, PET-70D, PET-75D); Adiprene® prepolymers(available from Chemtura, such as, LF 800A, LF 900A, LF 910A, LF 930A,LF 931A, LF 939A, LF 950A, LF 952A, LF 600D, LF 601D, LF 650D, LF 667,LF 700D, LF750D, LF751D, LF752D, LF753D and L325); Andur® prepolymers(available from Anderson Development Company, such as, 70APLF, 80APLF,85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, 75APLF).

Preferably, the isocyanate terminated urethane prepolymer is a low freeisocyanate terminated urethane prepolymer having less than 0.1 wt % freetoluene diisocyanate (TDI) monomer content.

The curative system used in the formation of the polishing layer of thechemical mechanical polishing pad of the present invention preferablycontains: 10 to 60 wt % (preferably 15 to 50 wt %; more preferably 20 to40 wt %; most preferably 20 to 30 wt %) of a high molecular weightpolyol curative; and, 40 to 90 wt % (preferably 50 to 85 wt %; morepreferably 60 to 80 wt %; most preferably 70 to 80 wt %) of adifunctional curative.

Preferably, the high molecular weight polyol curative has a numberaverage molecular weight, M_(N), of 2,500 to 100,000. More preferably,the high molecular weight polyol curative used has a number averagemolecular weight, M_(N), of 5,000 to 50,000 (still more preferably 7,500to 25,000; most preferably 10,000 to 12,000).

Preferably, the high molecular weight polyol curative has an average ofthree to ten hydroxyl groups per molecule. More preferably, the highmolecular weight polyol curative used has an average of four to eight(still more preferably five to seven; most preferably six) hydroxylgroups per molecule.

Examples of commercially available high molecular weight polyolcuratives include Specflex® polyols, Voranol® polyols and Voralux®polyols (available from The Dow Chemical Company); Multranol® SpecialtyPolyols and Ultracel® Flexible Polyols (available from BayerMaterialScience LLC); and Pluracol® Polyols (available from BASF). Anumber of preferred high molecular weight polyol curatives are listed inTABLE 1.

TABLE 1 Number of Hydroxyl High molecular weight OH groups Number polyolcurative per molecule M_(N) (mg KOH/g) Multranol ® 3901 Polyol 3.0 6,00028 Pluracol ® 1385 Polyol 3.0 3,200 50 Pluracol ® 380 Polyol 3.0 6,50025 Pluracol ® 1123 Polyol 3.0 7,000 24 ULTRACEL ® 3000 Polyol 4.0 7,50030 SPECFLEX ® NC630 Polyol 4.2 7,602 31 SPECFLEX ® NC632 Polyol 4.78,225 32 VORALUX ® HF 505 Polyol 6.0 11,400 30 MULTRANOL ® 9185 Polyol6.0 3,366 100 VORANOL ® 4053 Polyol 6.9 12,420 31

Preferably, the difunctional curative is selected from diols anddiamines. More preferably, the difunctional curative used is a diamineselected from the group consisting of primary amines and secondaryamines. Still more preferably, the difunctional curative used isselected from the group consisting of diethyltoluenediamine (DETDA);3,5-dimethylthio-2,4-toluenediamine and isomers thereof;3,5-diethyltoluene-2,4-diamine and isomers thereof (e.g.,3,5-diethyltoluene-2,6-diamine);4,4′-bis-(sec-butylamino)-diphenylmethane;1,4-bis-(sec-butylamino)-benzene; 4,4′-methylene-bis-(2-chloroaniline);4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA);polytetramethyleneoxide-di-p-aminobenzoate; N,N′-dialkyldiamino diphenylmethane; p,p′-methylene dianiline (MDA); m-phenylenediamine (MPDA);4,4′-methylene-bis-(2-chloroaniline) (MBOCA);4,4′-methylene-bis-(2,6-diethylaniline) (MDEA);4,4′-methylene-bis-(2,3-dichloroaniline) (MDCA);4,4′-diamino-3,3′-diethyl-5,5′-dimethyl diphenylmethane,2,2′,3,3′-tetrachloro diamino diphenylmethane; trimethylene glycoldi-p-aminobenzoate; and mixtures thereof. Most preferably, the diaminecuring agent used is selected from the group consisting of4,4′-methylene-bis-(2-chloroaniline) (MBOCA);4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA); and, isomersthereof.

Preferably, the sum of the reactive hydrogen groups (i.e., the sum ofthe amine (NH₂) groups and the hydroxyl (OH) groups) contained in thecomponents of the curative system (i.e., the high molecular weightpolyol curative and the difunctional curative) divided by the unreactedisocyanate (NCO) groups in the isocyanate terminated urethane prepolymer(i.e., the stoichiometric ratio) used in the formation of the polishinglayer of the chemical mechanical polishing pad of the present inventionis preferably 0.85 to 1.15 (more preferably 0.85 to 1.05; mostpreferably 0.85 to 1.0).

The polishing layer of the chemical mechanical polishing pad of thepresent invention optionally further comprises a plurality ofmicroelements. Preferably, the plurality of microelements are uniformlydispersed throughout the polishing layer. Preferably, the plurality ofmicroelements is selected from entrapped gas bubbles, hollow corepolymeric materials, liquid filled hollow core polymeric materials,water soluble materials and an insoluble phase material (e.g., mineraloil). More preferably, the plurality of microelements is selected fromentrapped gas bubbles and hollow core polymeric materials uniformlydistributed throughout the polishing layer. Preferably, the plurality ofmicroelements has a weight average diameter of less than 150 μm (morepreferably of less than 50 μm; most preferably of 10 to 50 μm).Preferably, the plurality of microelements comprise polymericmicroballoons with shell walls of either polyacrylonitrile or apolyacrylonitrile copolymer (e.g., Expancel® microspheres from AkzoNobel). Preferably, the plurality of microelements are incorporated intothe polishing layer at 0 to 35 vol % porosity (more preferably 10 to 25vol % porosity).

The polishing layer of the chemical mechanical polishing pad of thepresent invention can be provided in both porous and nonporous (i.e.,unfilled) configurations. Preferably, the polishing layer of thechemical mechanical polishing pad of the present invention exhibits adensity of ≥0.6 g/cm³ as measured according to ASTM D1622. Morepreferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a density of 0.7 to 1.1 g/cm³ (morepreferably, 0.75 to 1.0; most preferably, 0.75 to 0.95) as measuredaccording to ASTM D1622.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a Shore D hardness of 40 to 60 asmeasured according to ASTM D2240. More preferably, the polishing layerof the chemical mechanical polishing pad of the present inventionexhibits a Shore D hardness of 45 to 55 (most preferably 50 to 55) asmeasured according to ASTM D2240.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits an elongation to break of 125 to 300%(more preferably, 140 to 300%; most preferably, 150 to 200%) as measuredaccording to ASTM D412.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a wet cut rate of 4 to 10 μm/min asmeasured using the method described herein in the Examples. Morepreferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a wet cut rate of 4.5 to 7 μm/min(still more preferably, 4.5 to 6 μm/min; most preferably, 4.5 to 5.5μm/min) as measured using the method described herein in the Examples.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a shear modulus (at 30° C.), G′₃₀, of50 to 250 MPa (more preferably, 50 to 200 MPa; most preferably, 100 to200 MPa) as measured according to ASTM D5279-13.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a shear modulus (at 40° C.), G′₄₀, of45 to 200 MPa as measured according to ASTM D5279-13.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a shear loss modulus (at 40° C.),G″₄₀, of 3 to 20 MPa as measured according to ASTM D5279-13.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a G′ 30/90 ratio of 1.5 to 4 (morepreferably, 2 to 4) as measured according to ASTM D5279-13.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a toughness of 20 to 70 MPa (morepreferably, 20 to 50 MPa; most preferably, 25 to 40 MPa) as measuredaccording to ASTM D1708-10.

Preferably, the polishing layer of the chemical mechanical polishing padof the present invention exhibits a tensile strength of 10 to 35 MPa(more preferably, 15 to 30 MPa; most preferably, 15 to 25 MPa) asmeasured according to ASTM D1708-10.

Polishing layer materials exhibiting high elongation to break valuestend to reversibly deform when subjected to machining operations, whichresults in groove formation that is unacceptably poor and texturecreation during diamond conditioning that is insufficient. The uniquecurative system used in the formation of the polishing layer of thechemical mechanical polishing pad of the present invention provides bothShore D hardness of 40 to 60 coupled with an elongation to break of 125to 300% as measured according to ASTM D412. Preferably, the polishinglayer of the chemical mechanical polishing pad of the present inventionexhibits both a Shore D hardness of 40 to 60 (preferably, 45 to 55; morepreferably, 50 to 55) and an elongation to break of 140 to 300%(preferably 150 to 300%; more preferably 150 to 200%) as measuredaccording to ASTM D412.

Softer polishing layer materials tend to polish substrates at a lowerrate than harder polishing layer materials. Notwithstanding, softerpolishing layer materials tend to create fewer polishing defects thanharder polishing layer materials. The unique curative system used in theformation of the polishing layer of the chemical mechanical polishingpad of the present invention provides an improved TEOS_(300-RR)/Shore Dhardness of ≥28 (preferably, of 28 to 100; more preferably, of 30 to 60;most preferably, of 30 to 50), wherein the TEOS_(300-RR)/Shore Dhardness is measured under the conditions set forth herein in theExamples.

Preferably, the polishing layer has an average thickness of 20 to 150mils. More preferably, the polishing layer has an average thickness of30 to 125 mils (still more preferably 40 to 120 mils; most preferably 50to 100 mils).

Preferably, the chemical mechanical polishing pad of the presentinvention is adapted to be interfaced with a platen of a polishingmachine. Preferably, the chemical mechanical polishing pad is adapted tobe affixed to the platen of a polishing machine. Preferably, thechemical mechanical polishing pad can be affixed to the platen using atleast one of a pressure sensitive adhesive and vacuum.

The chemical mechanical polishing pad of the present inventionoptionally further comprises at least one additional layer interfacedwith the polishing layer. Preferably, the chemical mechanical polishingpad optionally further comprises a compressible base layer adhered tothe polishing layer. The compressible base layer preferably improvesconformance of the polishing layer to the surface of the substrate beingpolished.

An important step in substrate polishing operations is determining anendpoint to the process. One popular in situ method for endpointdetection involves providing a polishing pad with a window, which istransparent to select wavelengths of light. During polishing, a lightbeam is directed through the window to the substrate surface, where itreflects and passes back through the window to a detector (e.g., aspectrophotometer). Based on the return signal, properties of thesubstrate surface (e.g., the thickness of films thereon) can bedetermined for endpoint detection purposes. To facilitate such lightbased endpoint methods, the chemical mechanical polishing pad of thepresent invention, optionally further comprises an endpoint detectionwindow. Preferably, the endpoint detection window is selected from anintegral window incorporated into the polishing layer; and, a plug inplace endpoint detection window block incorporated into the chemicalmechanical polishing pad. One of ordinary skill in the art will know toselect an appropriate material of construction for the endpointdetection window for use in the intended polishing process.

Preferably, the method of making a chemical mechanical polishing pad ofthe present invention, comprises: providing an isocyanate terminatedurethane prepolymer having 8.5 to 9.5 wt % (preferably, 8.75 to 9.5 wt%; more preferably, 8.75 to 9.25; most preferably, 8.95 to 9.25 wt %)unreacted NCO groups; and, providing a curative system, comprising: (i)providing 10 to 60 wt % (preferably, 15 to 50 wt %; more preferably, 20to 40 wt %; most preferably, 20 to 30 wt %) of a high molecular weightpolyol curative, wherein the high molecular weight polyol curative has anumber average molecular weight, M_(N), of 2,500 to 100,000 (preferably5,000 to 50,000; more preferably 7,500 to 25,000; most preferably,10,000 to 12,000); and wherein the high molecular weight polyol curativehas an average of three to ten (preferably, four to eight; morepreferably, five to seven; most preferably, six) hydroxyl groups permolecule; and, (ii) providing 40 to 90 wt % (preferably, 50 to 85 wt %;more preferably, 60 to 80 wt %; most preferably, 70 to 80 wt %) of adifunctional curative; combining the isocyanate terminated urethaneprepolymer and the curative system to form a combination; allowing thecombination to react to form a product; forming a polishing layer fromthe product; and, forming the chemical mechanical polishing pad with thepolishing layer.

The method of making a chemical mechanical polishing pad of the presentinvention, optionally, further comprises: providing a plurality ofmicroelements; and, wherein the plurality of microelements is combinedwith the isocyanate terminated urethane prepolymer and the curativesystem to form the combination.

The method of making a chemical mechanical polishing pad of the presentinvention, optionally, further comprises: providing a mold; pouring thecombination into the mold; and, allowing the combination to react in themold to form a cured cake; wherein the polishing layer is derived fromthe cured cake. Preferably, the cured cake is skived to derive multiplepolishing layers from a single cured cake. Optionally, the methodfurther comprises heating the cured cake to facilitate the skivingoperation. Preferably, the cured cake is heated using infrared heatinglamps during the skiving operation in which the cured cake is skivedinto a plurality of polishing layers.

The method of making the chemical mechanical polishing pad of thepresent invention, optionally, further comprises: providing at least oneadditional layer; and, interfacing the at least one additional layerwith the polishing layer to form the chemical mechanical polishing pad.Preferably, the at least one additional layer is interfaced with thepolishing layer by known techniques, such as, by using an adhesive(e.g., a pressure sensitive adhesive, a hot melt adhesive, a contactadhesive).

The method of making the chemical mechanical polishing pad of thepresent invention, optionally, further comprises: providing an endpointdetection window; and, incorporating the endpoint detection window intothe chemical mechanical polishing pad.

The method of the present invention for chemical mechanical polishing ofa substrate preferably comprises: providing a chemical mechanicalpolishing apparatus having a platen; providing at least one substrate tobe polished (preferably, wherein the substrate is selected from thegroup consisting of at least one of a magnetic substrate, an opticalsubstrate and a semiconductor substrate; more preferable, wherein thesubstrate is a semiconductor substrate; most preferably, wherein thesubstrate is a semiconductor wafer with an exposed TEOS surface);providing a chemical mechanical polishing pad of the present invention;installing onto the platen the chemical mechanical polishing pad;optionally, providing a polishing medium at an interface between apolishing surface of the chemical mechanical polishing pad and thesubstrate (preferably, wherein the polishing medium is selected from thegroup consisting of a polishing slurry and a non-abrasive containingreactive liquid formulation); creating dynamic contact between thepolishing surface and the substrate, wherein at least some material isremoved from the substrate; and, optionally, conditioning of thepolishing surface with an abrasive conditioner. Preferably, in themethod of the present invention, the chemical mechanical polishingapparatus provided further includes a light source and a photosensor(preferably a multisensor spectrograph); and, the chemical mechanicalpolishing pad provided further includes an endpoint detection window;and, the method further comprises: determining a polishing endpoint bytransmitting light from the light source through the endpoint detectionwindow and analyzing the light reflected off the surface of thesubstrate back through the endpoint detection window incident upon thephotosensor.

Some embodiments of the present invention will now be described indetail in the following Examples.

Comparative Examples C1-C9 and Examples 1-14

Polishing layers were prepared according to the formulation detailsprovided in TABLE 2. Specifically, polyurethane cakes were prepared bythe controlled mixing of the isocyanate terminated urethane prepolymerat 51° C. with the components of the curative system. All of the rawmaterials, except for MBOCA, were maintained at a premixing temperatureof 51° C. The MBOCA was maintained at a premixing temperature of 116° C.The ratio of the isocyanate terminated urethane prepolymer and thecurative system was set such that the stoichiometry, as defined by theratio of active hydrogen groups (i.e., the sum of the —OH groups and—NH₂ groups) in the curatives of the curative system to the unreactedisocyanate (NCO) groups in the isocyanate terminated urethaneprepolymer, was as noted in TABLE 2.

Porosity was introduced into the polishing layers by adding Expancel®microspheres to the isocyanate terminated urethane prepolymer prior tocombining with the curative system to achieve the desired porosity andpad density. The grade of Expancel® microspheres added in each ofComparative Examples C1-C9 and Examples 1-14 is noted in TABLE 2 alongwith the amount of the pore former added in wt %. Expancel® microspheresare available from Akzo Nobel.

The isocyanate terminated urethane prepolymer with the incorporatedExpancel® microspheres and the curative system were mixed together usinga high shear mix head. After exiting the mix head, the combination wasdispensed over a period of 2 to 5 minutes into a 86.4 cm (34 inch)diameter circular mold to give a total pour thickness of 7 to 10 cm. Thedispensed combination was allowed to gel for 15 minutes before placingthe mold in a curing oven. The mold was then cured in the curing ovenusing the following cycle: 30 minutes ramp from ambient temperature to aset point of 104° C., then hold for 15.5 hours at 104° C., and then 2hour ramp from 104° C. to 21° C.

The cured polyurethane cakes were then removed from the mold and skived(cut using a moving blade) at a temperature of 30 to 80° C. intoapproximately forty separate 2.0 mm (80 mil) thick sheets. Skiving wasinitiated from the top of each cake. Any incomplete sheets werediscarded.

TABLE 2 Isocyanate terminated Curative System Stoich. Expancel ® Poreurethane Difunctional DC Voralux ® HF 505 (Active Pore Former PorosityEx # prepolymer (% NCO) curative (DC) (wt %) (wt %) H/NCO) Former (wt %)(vol %) C1 Adiprene ® L325 9.1 MbOCA 100 — 0.87 551DE40d42 1.70 32 C2Adiprene ® LF750D 8.9 MbOCA 100 — 1.05 551DE20d60 1.10 19 C3 Adiprene ®LFG740D 8.9 MbOCA 100 — 0.91 551DE40d42 0.19 9 C4 50/50 wt % blend of7.3 MbOCA 100 — 0.97 551DE20d60 2.00 31 Adiprene ® LF750D Adiprene ®LFG963A C5 80/20 wt % blend of 8.3 MbOCA 100 — 0.89 461DE20d70 2.59 31Adiprene ® LF750D Adiprene ® LFG963A C6 70/30 wt % blend of 7.9 MbOCA100 — 0.89 461DE20d70 2.59 31 Adiprene ® LF750D Adiprene ® LFG963A C750/50 wt % blend of 7.3 MbOCA 100 — 0.87 461DE20d70 2.85 32 Adiprene ®LF750D Adiprene ® LFG963A C8 Adiprene ® LFG963A 5.7 MCDEA 100 — 1.03461DE20d70 2.06 27 C9 Adiprene ® LFG963A 5.7 MbOCA 100 — 0.90 551DE40d421.25 25 1 Adiprene ® L325 9.1 MbOCA 42.2 57.8 0.87 461DE20d70 2.48 30 2Adiprene ® L325 9.1 MbOCA 42.5 57.5 0.87 461DE20d70 1.38 21 3 Adiprene ®L325 9.1 MbOCA 49.6 50.4 0.87 461DE20d70 2.58 31 4 Adiprene ® L325 9.1MbOCA 50.0 50.0 0.87 461DE20d70 1.41 23 5 Adiprene ® L325 9.1 MbOCA 53.546.5 1.05 461DE20d70 2.48 29 6 Adiprene ® L325 9.1 MbOCA 53.9 46.1 1.05461DE20d70 1.42 20 7 Adiprene ® L325 9.1 MbOCA 58.6 41.4 0.87 461DE20d702.69 30 8 Adiprene ® L325 9.1 MbOCA 59.0 41.0 0.87 461DE20d70 1.45 19 9Adiprene ® L325 9.1 MbOCA 62.3 37.7 1.05 461DE20d70 2.59 31 10Adiprene ® L325 9.1 MbOCA 62.6 37.4 1.05 461DE20d70 1.47 24 11Adiprene ® L325 9.1 MbOCA 75.0 25.0 0.87 461DE20d70 2.85 32 12Adiprene ® L325 9.1 MbOCA 77.7 22.3 1.05 461DE20d70 2.74 30 13Adiprene ® L325 9.1 MbOCA 77.9 22.1 1.05 461DE20d70 1.50 23 14Adiprene ® L325 9.1 MbOCA 86.2 13.8 0.87 461DE20d70 2.94 33 Adiprene ®L325 isocyanate terminated urethane prepolymer is available fromChemtura Corporation. Adiprene ® LF750D isocyanate terminated urethaneprepolymer is available from Chemtura Corporation. Adiprene ® LFG740Disocyanate terminated urethane prepolymer is available from ChemturaCorporation. Adiprene ® LFG963A isocyanate terminated urethaneprepolymer is available from Chemtura Corporation. Voralux ® HF505 highmolecular weight polyol curative having a number average molecularweight, M_(N), of 11,400 and an average of six hydroxyl groups permolecule is available from The Dow Chemical Company.

The ungrooved, polishing layer materials from each of ComparativeExamples C1-C9 and Examples 1-14 were analyzed to determine theirphysical properties as reported in TABLE 3. Note that the density datareported were determined according to ASTM D1622; the Shore D hardnessdata reported were determined according to ASTM D2240; and, theelongation to break data reported were determined according to ASTMD412.

The shear modulus, G′, and the shear loss modulus, G″, of the polishinglayers were measured according to ASTM D5279-13 using a TA InstrumentsARES Rheometer with torsion fixtures. Liquid nitrogen that was connectedto the instrument was used for sub-ambient temperature control. Thelinear viscoelastic response of the samples was measured at a testfrequency of 1 Hz with a temperature ramp of 3° C./min from −100° C. to200° C. The test samples were stamped out of product polishing layersusing a 47.5 mm×7 mm die on an Indusco hydraulic swing arm cuttingmachine and then cut down to approximately 35 mm in length usingscissors.

The cut rate data reported in TABLE 3 were measured using a BuehlerEcomet® 4 polisher outfitted with an Automet® 2 power head. Thepolishing tool is designed to accommodate a circular chemical mechanicalpolishing pad having a nominal diameter of 22.86 cm (9 inches).Polishing layers having a circular cross section were prepared asdescribed herein in the Examples. The polishing layers were mounted tothe polishing platen of the polisher using a double sided pressuresensitive adhesive film.

An LPX-AR3B66 (LPX-W) diamond conditioning disk (commercially availablefrom Saesol Diamond Ind. Co., Ltd.) and an AM02BSL8031C1-PM (AK45)diamond conditioning disk (also commercially available from SaesolDiamond Ind. Co., Ltd.) were used to abrade the polishing surface of thepolishing layers as reported in TABLE 3 using the following processconditions: the polishing surface of the polishing layers were subjectedto continuous abrasion from the diamond conditioning disk for a periodof 99 minutes, with a platen speed of 180 rpm, a deionized water flowrate of 280 mL/min and a conditioning disk down force of 55.16 kPa (8psi). The cut rate was determined by measuring the change in polishinglayer thickness over time. The polishing layer thickness change wasmeasured (in μm/min) using an MTI Instruments Microtrack II LaserTriangulation Sensor mounted on a Zaber Technologies Motorized Slide toprofile the polishing surface of each polishing layer from the center tothe outer edge. The sweep speed of the sensor on the slide was 0.732mm/s and the sampling rate (measurements/mm of sweep) for the sensor was6.34 points/mm. The cut rate reported in TABLE 3 is the arithmeticaverage reduction in polishing layer thickness over time, based on thecollected thickness measurements taken as >2,000 points across thepolishing surface of the polishing layer.

TABLE 3 Shore D G′ @ G′ @ G″ @ Tensile Elongation Tensile Wet cut rateDensity (15 s) 30° C. 40° C. 40° C. G′@30° C./ strength to break modulusToughness (μm/min) Ex. # (g/cm³) Hardness (MPa) (MPa) (MPa) G′@90° C.(MPa) (%) (MPa) (MPa) LPX-W AK45 C1 0.80 59 153 130 13.0 3.4 22.1 124206 24 — — C2 0.95 60 153 122 15.0 3.3 30.6 199 303 — 3.7 2.8 C3 1.07 63230 199 17.0 2.2 — — — — 3.9 2.8 C4 0.82 50 105 92 8.6 2.7 18.8 230 18535 4.9 — C5 0.82 58 — — — — — — — — — — C6 0.82 53 — — — — — — — — — —C7 0.80 51 — — — — — — — — — — C8 0.86 46 87 81 5.5 1.7 17.9 470 172 63— — C9 0.88 41 64 49 3.2 1.9 14.9 293 95 32 2.5 3.2 1 0.83 44 73 64 6.12.3 15.3 223 129 42 6.7 6.3 2 0.93 49 80 69 7.1 2.2 19.8 290 138 26 — —3 0.82 47 88 77 6.8 2.6 17.6 238 149 33 6.2 — 4 0.91 52 99 86 7.8 2.422.3 247 164 41 — — 5 0.84 49 103 89 9.3 2.7 17.2 231 188 33 — — 6 0.9454 123 106 10.6 2.7 22.7 294 207 52 — — 7 0.83 50 105 92 8.7 2.6 19.5211 173 33 5.9 6.7 8 0.95 54 126 107 10.2 2.6 23.6 237 193 43 5.1 — 90.82 51 182 155 13.0 3.3 19.0 243 192 37 — — 10 0.90 53 144 123 12.2 3.123.5 280 230 51 — — 11 0.80 52 140 119 12.0 3.0 20.7 184 199 31 4.9 6.612 0.93 53 174 148 15.5 3.3 20.3 205 223 35 — — 13 0.91 57 165 136 15.43.8 25.0 259 272 52 — — 14 0.79 54 154 131 12.6 3.1 21.8 147 222 26 5.05.7

Polishing Experiments

Chemical mechanical polishing pads were constructed using polishinglayers prepared according to the Examples as noted in noted in Table 4.These polishing layers were then machine grooved to provide a groovepattern in the polishing surface comprising a plurality of concentriccircular grooves having dimensions of 70 mil (1.78 mm) pitch, 20 mil(0.51 mm) width and 30 mil (0.76 mm) depth. The polishing layers werethen laminated to a foam sub-pad layer (FSP 350 available from Rohm andHaas Electronic Materials CMP Inc.).

An Applied Materials Reflexion LK® CMP polishing platform was used topolish 300 mm 3S20KTEN TEOS (oxide) blanket wafers available fromNovellus Systems, Inc. with the noted chemical mechanical polishingpads. The polishing medium used in the polishing experiments was aCES333F polishing slurry (1:2 dilution ratio with deionizedwater)(commercially available from Asahi Glass Company). The polishingconditions used in all of the polishing experiments included a platenspeed of 92 rpm; a carrier speed of 93 rpm; with a polishing medium flowrate of 250 ml/min and a down force of 20.7 kPa. An I-PDA31G-3N diamondconditioning disk (commercially available from Kinik Company) was usedto condition the chemical mechanical polishing pads. The chemicalmechanical polishing pads were each broken in with the conditioner exsitu using a down force of 7.5 lbs (3.40 kg) for 40 minutes. Thepolishing pads were further conditioned ex situ prior to polishing usinga down force of 7.5 lbs (3.40 kg) for 18 seconds. The removal rates weredetermined by measuring the film thickness before and after polishingusing a KLA-Tencor FX200 metrology tool using a 49 point spiral scanwith a 3 mm edge exclusion. The results of the removal rate experimentsare provided in TABLE 4.

TABLE 4 Polishing TEOS TEOS_(300-RR)/ layer of removal rate Shore DHardness Ex. # (Å/min) (Å/min) C1 1518 25.73 C7 1401 27.47  5 2365 48.27 6 1696 31.41  9 2149 42.14 10 1495 28.21 11 1780 34.23 12 2633 49.68 131986 34.84

We claim:
 1. A chemical mechanical polishing pad adapted for polishing a substrate selected from the group consisting of at least one of a magnetic substrate, an optical substrate and a semiconductor substrate, comprising: a polishing layer adapted for polishing a substrate selected from the group consisting of at least one of a magnetic substrate, an optical substrate and a semiconductor substrate having a polishing surface, wherein the polishing layer comprises a reaction product of ingredients, comprising: an isocyanate terminated urethane prepolymer having 8.75 to 9.25 wt % unreacted NCO groups; and, a curative system consisting essentially of: 20 to 30 wt % of a high molecular weight polyol curative, wherein the high molecular weight polyol curative has a number average molecular weight, Mn, of 10,000 to 12,000; and wherein the high molecular weight polyol curative has an average of 6 hydroxyl groups per molecule; and, 70 to 80 wt % of a 4,4′-methylene-bis-(2-chloroaniline) (MbOCA) difunctional curative wherein the polishing layer exhibits a density of greater than 0.6 g/cm³; a Shore D hardness of 40 to 60; an elongation to break of 125 to 300%; a G′ 30/90 ratio of 1.5 to 4; a tensile modulus of 100 to 300 (MPa); a wet cut rate of 4 to 10 μm/min; and, a 300 mm TEOS removal rate to Shore D hardness ratio (TEOS_(300-RR)/Shore D hardness) of ≥28.
 2. The chemical mechanical polishing pad of claim 1, wherein the curative system has a plurality of reactive hydrogen groups and the isocyanate terminated urethane prepolymer has a plurality of unreacted NCO groups; and, wherein a stoichiometric ratio of the reactive hydrogen groups to the unreacted NCO groups is 0.85 to 1.15.
 3. The chemical mechanical polishing pad of claim 1, wherein the isocyanate terminated urethane prepolymer has 8.95 to 9.25 unreacted NCO groups.
 4. The chemical mechanical polishing pad of claim 1, wherein the polishing surface has a spiral groove pattern formed therein.
 5. The chemical mechanical polishing pad of claim 1, wherein the MN of the high molecular weight polyol curative is about 11,400. 